Ink transfer system

ABSTRACT

An ink transfer system for a rotary printing press wherein a helically grooved transfer roll is provided for effectively transferring toward a plate cylinder an ink volume consistent or equal to the usage requirements at any given point or area on the roll surface as determined by the printed image. The transfer roll has the ability to simultaneously transfer ink reversely back onto the fountain roll by reason of its helical grooves being in light contact with a relatively slowly rotating fountain roll. An offset groove and ball arrangement is provided for one of the distribution rolls in the printing press chain of rollers so as to smoothly oscillate the roll for a more even distribution of the ink transversely of each roll in the ink train. The inner face of each fountain roll mount is slightly relieved so as to direct ink away from the outermost ends of the fountain roll thereby substantially preventing fountain leakage.

limited States Harrod [451 Mar. 28, 1972 [73] Assignee: Moore Business Forms, Inc., Niagara Falls,

[22] Filed: Dec. 17, 1969 [21] Appl.No.: 885,748

Primary Examiner-Clyde I. Coughenour Attorney-Watson, Cole, Grindle & Watson [57] ABSTRACT An ink transfer system for a rotary printing press wherein a helically grooved transfer roll is provided for effectively transferring toward a plate cylinder an ink volume consistent or equal to the usage requirements at any given point or area on the roll surface as determined by the printed image. The transfer roll has the ability to simultaneously transfer ink reversely back onto the fountain roll by reason of its helical grooves being in light contact with a relatively slowly rotating fountain roll. An offset groove and ball arrangement is provided for one of the distribution rolls in the printing press chain of rollers so as to smoothly oscillate the roll for a more even distribution of the ink transversely of each roll in the ink train. The inner face of each fountain roll mount is slightly relieved so as to direct ink away from the outermost ends of the fountain roll thereby substantially preventing fountain leakage.

8 Claims, 7 Drawing Figures IN K TRANSFER SYSTEM This invention relates generally to printing presses and more particularly to an ink transfer system having a transfer roll designed for maintaining a more complete balance of ink film in the system by permitting both a forward and reverse transfer during rotation in one continuous direction.

One of the inherent difficulties in printing with the rotary printing press lies in the repeated failure to achieve a suitable balance ofink through the system so that as ink is consumed at the plate cylinder only an appropriate ink volume consistent with that usage will be transferred from the fountain. The presence of too little or too much ink on the printed image requires the printer to first adjust the extrusion through the fountain blade through a process of trial and error, while the press is in operation, until the desired printed image is achieved. During this interval an extensive amount of paper and man-hours are wasted because the increased or decreased amount of ink extruded by the fountain blade must be circulated through the system and the paper with its unwanted image mustbe expelled through the systemcompletely before the press becomes once again productive. Also, for the wide viscosity range of different inks used during printing, a new adjustment is required so that many rotary printing presses are not tailored for effective transfer of these various grades of ink in a manner whereby a constant ink film thickness onto the plate cylinder is assured regardless of ink density.

In an attempt to remedy this situation, various means have been developed for reducing the film thickness from the fountain roll and evenly spreading the film during its travel toward the plate cylinder. For example, ductor rollers have been extensively employed for effecting intermittent contact between the fountain and a first distribution roll. However, this technique only tends to produce undesirable variations in the film which are difficult to smoothen even with the use of a long chain of distribution rollers. Another technique includes the use of either a smooth transfer roll or one having spiral ridges or other types of elevated designs thereon. Such types of transfer rolls prove to be ineffective since they only tend to pick up the ink in uneven patches and thereafter deposit it unevenly.

Also, in rotary press systems, leakage of ink through the fountain has been an almost never ending problem in the industry. In most current designs the length of each fountain roll must be precisely machined so as the lie within a close clearance at both ends against each fountain cheek. After extended use these clearances tend to enlarge to such an extent that leakage occurs as beads ofink escape between the ends of the fountain blade and the inner face of each fountain cheek. Other than a repeated wiping of this area, steps have been taken to avoid leakage by designing the fountain cheeks as having slightly sloping surfaces near the top of their inner faces so that, after the beads ofink travel between the point of leakage and the top of each cheek inner face, they will return back into the fountain reservoir. This technique has not substantially reduced leakage because it has been found that most of the ink beads will merely drip from the cheek under the force of gravity before travelling around the cheek surface toward the relief. in the present invention, the fountain roll is mounted so that each end of its roll surface lies within each end mount or cheek which is designed as having a relief presenting a sharp edge in line with the ends of the fountain blade so that the beads of ink may be directed away from the surface of each cheek directly onto the fountain roll and finally back into the fountain reservoir.

Another problem in rotary printing presses arousing somewhat of a concern in the industry involves the currently available technique for oscillating one or more rolls in the system so as to more evenly distribute the ink film across each roll. This technique makes use of a worm gear and worm for transmitting axial movement to the oscillating roll. Each of the several moving parts therein require maintenance and periodic replacement which only increases the probability of costly downtime for the equipment and additional expenses in operation. With the present vibration system. a ball of a specified diameter is mounted for rotation and planetary movement about the oscillator roll within an offset groove designed at one end of its axle. Accordingly, fewer moving parts are required which not only reduces the likelihood of extensive downtime of the equipment but also permits the oscillating axle to be moved directly by a force parallel thereto thereby avoiding undue wear otherwise attributable to the gear driven oscillators. Accordingly, the instant invention has for its main object the provision of an improved transfer roll for a rotary printing press which will transfer an ink volume consistent with usage requirements so that a more balanced ink film thickness is maintained in the system despite the variation of ink viscosity or the relative amount of ink being extruded through the fountain blade.

Another object of this invention is to provide an ink transfer system wherein the improved transfer roll is capable of simultaneously transferring an amount of ink in either or both directions through the system at a rate depending on the usage requirement and/or the change in the volume of ink available for transfer thereby achieving a more balanced ink distribution system.

A further object of the invention is to provide an ink transfer system wherein the improved transfer roll is slightly undersped with relation to press surface speed and the fountain roll is greatly undersped with respect to press surface speed so that, together with the specific type of transfer roll design, ink is transferred reversely even during forward transfer and, after drainage of ink from the fountain, will effect a total reverse transfer of ink back toward the fountain roll providing no additional ink is extruded by the fountain blade.

A still further object of this invention is to provide an ink transfer system wherein the surface of said transfer roll is provided with a plurality of grooves thereon each having at least one radial surface forming a sharp juncture with the outermost periphery of the roll surface whereby forward and reverse transfer is achieved at a rate depending upon the speed of rotation of the fountain roll.

A still further object of the instant invention is to provide a transfer roll as characterized wherein the sharp radial surface departure defines a trailing edge with respect to direction of roll rotation and wherein the lowermost surface of each groove joins the trailing edge of an adjacent groove thereby creating a leading edge or ramp between grooves whereby reverse ink transfer onto the fountain roll is effected through an ink spreading action caused by the leading and trailing edges rotating against the slower rotating fountain roll.

A still further object of this invention is to provide an improved oscillating means for the ink transfer system wherein one distribution roll in the ink train of rolls is smoothly oscillated by a force acting directly along its axis for evenly distributing the ink between the ends of each roll in the train.

A still further object of this invention is to provide such an oscillating means comprising an offset groove and ball arrangement at one end of one of the rolls in the train so that rotation of such roll causes axial movement as the offset groove moves about the planetary ball thereby directly transmitting a force along the axis of the roll.

A still further object of the present invention is to provide an ink transfer system utilizing such an oscillator means as characterized wherein a pair of ring members are provided for retaining the ball member in place against the side walls of the offset groove, the ring members being adjustable toward and away from each other in order to vary the bearing pressure of the ball member against the groove side walls.

A still further object of this invention is to provide an oscillator means for an ink transfer system wherein the ring members as described each have an inner surface forming an outer race for the ball member.

A still further object of the invention is to provide a technique for rendering the fountain substantially leakproof by avoiding the need for close clearance between each end of the fountain roll and the inner face of each fountain cheek A still further object of the present invention is to provide a leakproof fountain by mounting each end of the fountain roll surface within each fountain cheek which is relieved along its inner surface so as to direct beads of ink at each end of the fountain roll away from each cheek and back into the fountain reservoir.

A still further object is to provide such a relief for each cheek so as to present a sharp extension on each cheek directly aligned with the ends of the fountain blade whereby any leakage between the blade ends and each relief will be directed onto the fountain roll for subsequent deposit back into the fountain reservoir.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a representative showing of a typical ink train of rolls incorporating the present invention;

FIG. 2 is a side elevational view of the ink transfer roll according to the present invention;

FIG. 3 is a fragmentary sectional view of the ink transfer roll taken substantially along the line 3-3 of FIG. 2;

FIG. 4 is a view taken along the line of 44 of FIG. 1 showing an assembly of the fountain, fountain roll and fountain blade according to the present invention;

FIG. 5 is a side and partial sectional view taken substantially along the line 5-5 of FIG. 4',

FIG. 5A is a partial perspective showing the inner surface of a fountain cheek designed for preventing leakage; and

FIG. 6 is a sectional view of one end of the central roller in the ink roll train showing the oscillator means according to the present invention.

Turning now to the drawings wherein like reference characters refer to like and corresponding parts throughout the several views there is shown in FIG. 1 a schematic representation of a typical ink distribution chain of rolls in a rotary printing press incorporating the improved features of the instant invention. A rotatable central roll 10 is therein provided with distribution rolls 11 being rotatably mounted in surface-tosurface contact therewith. The rearwardmost distribution roll 11' is rotatably mounted in contact with the surface of transfer roll 13 of the present invention. This roll 13 is adjacent a fountain roll 14 which is rotatably mounted within an ink fountain 15 in a manner to be hereinafter described. At the other end ofthe array, the typical plate cylinder 16 is rotatably mounted in contact with two of the typically arranged form rolls 12. The surfaces of the several rolls in the train are alternately hard and soft so that the fountain roll 14, distribution roll 11, central roll 10 and the plate cylinder 16 may each have a metallic surface while the distribution rolls 11, the form rolls I2 and the transfer roll 13 may each have a rubberized or polyurethane or other resilient surface, as shown.

Transfer roll 13 is provided with a plurality of helical grooves 17 and, as can be seen in FIG. I, consist ofa total of eight grooves equally spaced about the surface of the roll. It should be understood, however, that as few as two and as many as l0 grooves are permissable depending on transfer roll diameter so that the specific number of grooves disclosed are not required in all applications. Each of the grooves 17 have only one side wall, as seen at 18 in FIG. 3, thereby presenting a sharp radial surface departure as at 19 which may be referred to as a trailing edge relative to the direction of rotation of the roll as shown by the arrow. The surface of transfer roll 13 between each of the grooves 17 is sloped between the uppermost portion of the groove side wall 18, i.e., trailing edge 19, and the lowermost portion of the groove side wall of an adjacent groove, i.e., bottom 21 of the groove. The slope is not along a straight line but is an arc length segment having a radius R with its radial center lying along the line L connecting the geometric center of the roll 13 and the outermost periphery thereof, as clearly shown in FIG. 3 of the drawings. The distance D from the geometric center of the roll 13 and the radial center ofline R is equal to 0. I25 inches in a roll having a diameter of approximately 3.5 inches. Although FIG. 3

SIM)

shows only two of the sloping surfaces of the roll 13, it should be understood that the above description for tracing an are between grooves is typical between all grooves.

FIG. 2 clearly shows each of the grooves 17 along the surface of roll 13 substantially parallel to one another and as most clearly seen for groove 17a, each groove terminates at each end of the roll on the hidden side of the roll surface as represented substantially by the broken lines 17a and 17a" for a single one of the grooves, similar showing for the remaining grooves being absent from the drawing in the interest of clarity.

In the ink train arrangement shown in FIG. I, the transfer roll 13 is undersped in relation to press speed so as to be rotated at approximately 83 /3 percent of press surface speed. The fountain roll, on the other hand, is rotated substantially below that of press surface speed so that it will be rotating at a rate between 0 and 6 /2 percent of press surface speed.

Returning to FIG. 3 of the drawings, it can be seen that the sloping arc length between each of the trailing edges 19 and the bottom potions 21 of an adjacent groove will actually produce a leading edge, slope or ramp 23.

All rolls in the system are set for a nominal squeeze contact of approximately 0.002 to 0.003 inch interference. This setting is sufficient to provide a rolling contact between rolls of approximately one-eighth inch on the circumference.

The transfer roll 13 is set for normal squeeze contact against the ink distribution roll 11' except that a running clearance is set at approximately 0.0005 inches maximum between the transfer roll and the fountain roll 14. This running clearance is necessary to prevent frictional heating of the two rolls due to the high surface speed differential which can be as much as 97 percent during actual printing conditions. During operation and rotating in a direction as shown by the arrows in FIG. 1, normal transfer of ink from the fountain roll to the plate cylinder is accomplished by the wiping action of the transfer roll generated ramps 23 from the fountain roll to the ink distribution roll 11. While the transfer roll 13 is rotating in this same direction, reverse transfer of ink is also taking place from the transfer roll 13 so that a quantity of ink is not only being removed from the fountain roll 14 but a quantity of ink is being redeposited back onto the fountain roll. Reverse transfer is, therefore, the process whereby the ink film is reduced and returned to the fountain roll 14 by action of the helical transfer roll. Ink is deposited on the fountain roll through a spreading action and subsequent ink-split caused by the sharp side 19 of the helical lead rotating against the slowly rotating fountain roll. The fountain roll is made to rotate between 0 and 6 /2 percent of press surface speed while the transfer roll is made to rotate approximately 83% percent of press surface speed. Reverse ink transfer through the ink spreading action as aforedescribed is made possible when the transfer roll is undersped by approximately 16% percent with respect to press surface speed. It has been found that, although reverse transfer is also possible when the transfer roll is driven at press speed, the rate of reverse transfer is approximately 50 percent slower as compared to reverse transfer during the 16% percent undersped relative rate of the transfer roll. Because of this simultaneous forward and reverse transfer by the roll 13, ink film on the surface of distribution roll 11 is actually being established by the difference between the wiping action of the leading side or ramp 23 against the fountain roll and the depositing action of the trailing edge 19 against the slower rotation of the fountain roll.

The above-referred-to ink-split condition is a commonly recognized term used to describe the resultant action that takes place after a given ink film thickness has been forced through the nip of two rolls in rolling contact. At the point of contact, the total film thickness on one or both rolls is blended and becomes common to both rolls as between the transfer roll 13 and the fountain roll 14. The ink-split condition then is the separation of the total film thickness at the point where the rolls cease to make rolling contact which would be at a slight distance from the point of roll contact in the direction of rotation of each roll. During ink splitting, a certain proportion of the total film thickness remains on each roll with the proportion being approximately equal assuming that both rolls have identical surface speeds at the point of contact. The actual proportion is determined by the relative surface speed of each roll and by the affinity of each roller surface. Therefore, the resultant ink film in the system is entirely dependent on the volume of ink supplied by the fountain through a combination of fountain film thickness and relative fountain speed. A nor mal printing film thickness of 0.0002 to 0.0004 inches is readily obtainable in the instant system by first adjusting the film thickness through the fountain blade to approximately 0.0007 to 0.001 inches depending upon the specific ink consistency, and thereafter regulating the rotational speed of the fountain roll.

The system film thickness is adjusted by varying the relative speed of the fountain roll over a 2:1 range of the given proportion of the press surface speed. An electronic fountain drive (not shown) operates between 3% and 6% percent of press speed, with the selected percentage being constant at any given press speed. The system ink film thickness may therefore be reduced at any time by merely decreasing the proportionate fountain roll speed.

Near total reverse transfer can be effected by completely stopping the fountain roll. Indexing of the fountain roll will therefore be required for this process, i.e., intermittent rotation of the fountain roll will best serve to effect total reverse transfer or clean-up. Accordingly, the fountain roll is rotated approximately 10 to in the normal direction of rotation at which time the roll remains in a stalled position for a maximum length of time, but not to exceed more than 180 seconds, this being the maximum automatic delay obtainable with an electronic timer contemplated for use with this invention. Stalling the fountain roll in this way permits ink to be deposited on the fountain roll at the juncture of the fountain and helical transfer roll. As the deposit increases, the fountain roll is rotated approximately 10 to 15 in the direction of the arrow as shown in FIG. 1 at the maximum length interval of 180 seconds as noted above. Any further rotation of the fountain roll other than as described could cause excess ink to be transferred to the system as in a normal operation. Accordingly, such indexing of the fountain roll prevents excess accumulation and possible runoff during use ofa more liquid ink.

For most formats the fountain roll can remain at the setting previously described during normal transfer (between 3% and 6% percent of press speed) since the helical transfer roll has excellent replenishment capabilities. However, the fountain roll blade gap setting may need to be readjusted during such times when an unusually heavy solid may appear on the format. Under normal operating conditions, it is desirable to obtain a proper balance of fountain roll film thickness and fountain roll speed so that the fountain roll speed is in the lower range of the electronic drive. This will tend to reduce any hydraulic action that may occur in the fountain, i.e., the dynamic force that tends to vary the fountain blade gap setting and thus vary the film thickness delivered by the fountain roll. This dynamic force is known to be caused by the rotation of the fountain roll past the stationary fountain blade. The actual force is developed through the ink itself as it is forced between the blade and fountain roll. Though the blade must be flexible to allow for minute gap adjustments across the roll, it is also susceptible to the hydraulic force applied at the juncture of the blade and fountain roll. Also, the hydraulic action varies with the speed of the fountain roll as well as with the viscosity of the ink. Forcing the ink through the blade gap also generates heat which is dependent upon the fountain roll speed and gap setting of the blade. Excessive heat will vary the viscosity of the ink and will cause a change in the fountain roll ink film thickness. It is, therefore, desirable to keep the speed of the fountain roll as slow as possible.

To summarize, it can be seen that the transfer action of the helical transfer roll 13 is effected by the rolling contact of the generated ramp 23 of each lead on the surface of the transfer roll. Each lead has an almost complete wiping action against the fountain roll due to the high surface speed differential of the transfer roll and fountain roll. Replenishment or transfer capability of the transfer roll therefore becomes less efficient as this rate of speed differential increases. On the other hand, return transfer or reverse transfer becomes more effective as this speed differential increases.

The amount of ink wiped from the fountain by each lead on the surface of the transfer roll is immediately transferred to the ink distribution roll 11 and thereafter to the distribution rolls 1], l0 and finally to the plate cylinder 16 through the form rolls 12. The sharp side or trailing edge 19 makes contact at approximately a 16% percent slower surface speed with the ink distribution roll 11' where a small amount of ink is thereupon forced into the radius of the groove 17 and is split and returned to where it again makes contact with the fountain roll. Because of the relative speeds of the rolls 11, 13 and 14 and due to their relative positions to each other as seen in FIG. 1, contact is made at the same radial position on the fountain roll where the film has been wiped by the leading edge of the same lead. At this point, the fountain film thickness is much less than the deposit on the trailing edge of the transfer roll lead. This reduced film thickness of the fountain roll and the deposit of the transfer roll combine and subsequently split through a spreading action caused by differential rolling contact thereby leaving a portion of the deposit on the fountain roll. When no ink is being consumed by the system and when an ink film balance has been achieved, i.e., the point at which equal amounts of ink are transferred in both directions, the helical transfer roll merely acts as a recirculating device. Therefore, when both ends of the roll cluster have identical film thickness, the ink film is merely recirculated through the ink-spliting process occurring at each roll contact.

Cleaning of the system can be readily accomplished more easily and efficiently by utilizing the reverse transfer function of the helical transfer roll. One way for accomplishing this reverse transfer would be to replace the fountain 15 with one containing no ink and adjust its fountain blade 24 so as to wipe the fountain roll clean. With the system operating in the normal direction of roll rotation as shown by the arrows in FIG. 1, no ink would be therefore supplied to the transfer roll 13. However, ink would be deposited on the clean fountain roll by the trailing side or edge 19 of each lead. This ink would be returned to the fountain reservoir area at which point it would be wiped from the fountain roll by the blade 24. An average system film thickness should be returned within a time equivalent of 1,000 to 1,500 surface feet of rotation, at which point a negligible film thickness may remain. Addition of cleaning solvent on the system rolls at this point would then remove most of the balance of the film.

An alternative technique for use during reverse ink transfer would be to completely stall the fountain roll or stall it to a negligible R.P.M. while the press is in the ink-up mode. This technique operates on much the same principle as the use of the clean fountain roll since no or only a negligible amount of ink is supplied to the transfer roll. Ink is deposited by the trailing edge of each lead at a point after the nip of the two rolls l3 and 14 causing an accumulation of ink to form at this point. Since this accumulation is formed after the nip, the normal wiping action of the leading ramp of each lead is not effective, and the lead tends to force the accumulated ink away from the nip rather than effect a transfer. As the accumulation increases on the fountain roll to a point of possible runoff or gravity transfer, the fountain roll must then be rotated toward the reservoir, if completely stalled.

Referring again to FIG. 1 of the drawings, it can be seen that the fountain blade 24 is mounted within the fountain 15 substantially below the level 1 of ink contained within the fountain. In FIGS. 4 and 5, it can be seen that the fountain comprises an elongated bottom or plate member 25 for supporting a quantity of ink and having end or cheek members 26 and 27 each suitably secured thereto as by fasteners 28. Cheek memlnin-m bers 26 and 27 serve as end walls for containing the ink and as a means for mounting the fountain roll 14, shown in FIG. as being journaled for rotation within a suitably provided aperture 30 in end member 26. The fountain blade 24 extends between the respective interior surfaces 260, 27a of each of the end members and is provided with a number of cutout portions 29 which, during assembly, permit the fountain blade to be adjusted relatively to the fountain roller against a pair of stop pins 31 clearly shown in both FIGS. 4 and 5. An elongated blade ciamp 32, having a number of threaded apertures 33 therealong for threaded engagement with a like number of threaded studs 40, serves as an elongated holddown means for securing one end of the fountain blade 24 in place after wing nuts 34 are sufficiently tightened about studs 40. A plurality of apertures 35 are also provided along the length of base member 25 and are internally threaded for the reception of a plurality of thumb screws 36 whereby an accurate adjustment of the forward edge of the fountain blade can be made along its entire length. Accordingly, the blade 24 may be first inserted into the fountain 15 so as to lie in contacting engagement with surfaces 26a, 27a at each side and against stop pins 31 at its forward end. Wing nuts 34 are then tightened and, by means of thumb screws 36, the blade gap is adjusted for regulating the amount of ink desired to be extruded through the blade.

Each of the inner surfaces 26a, 27a of the cheek members 26 and 27 is slightly relieved as at 37 in the vicinity of aperture 30, as seen in FIG. 5A, so that the width of each cheek at the relieved area is approximately one-sixteenth inch less than the width of the remainder of each cheek. As shown, the unrelieved portion of the cheek terminates at an end cap 37 defined by a well substantially perpendicular to blade 24 so that any leakage between face 27a and the side edge of the blade will occur at a distance equal to the relief forwardly of end cap 37'. The diameters of the aperture 30 and fountain roll are substantially equal so that the fountain roll ends are each received wholly within the aperture 30 to each cheek. Accordingly, any leakage between the cheek inner faces and the blade ends will result in beads of ink being directed onto a portion of the fountain roll surface, rather than hugging the inner face of each cheek where accumulation of ink normally builds up and subsequently drips downwardly. The undesirable beads of ink directed onto the fountain roll surface, therefore, are directed back into the fountain reservoir as the fountain roll continues to rotate. In order to ensure that these beads will not cause an undue amount of ink accumulation at the faces 26a, 270, a chamfered wall section 37" is provided for the upper section of the relief, as shown clearly in FIG. 5A. Pressure buildup, occasioned by hydraulic action of the ink at either end ofthe fountain roll, is thereby relieved somewhat so that any leakage through the fountain may be held to a minimum.

It has been found that with an adjustment of the fountain blade against the fountain roll to effect a fountain film thickness between 0.0007 and 0.0010 inches, and with the fountain drive in the low speed range, the resultant film thickness should be about 0.0002 to 0.0003 inches, which is in the lower portion of the normal printing range. If the film is not sufficient for the format and ink being used, the thickness may be increased by merely increasing the relative speed of the fountain roll. Conversely, if the ink film becomes excessive, the system film thickness may be reduced by either reducing the relative speed of the fountain or by reducing the fountain roll film thickness by narrowing the blade gap.

A simple unique oscillating mechanism for the sum axle 38 of the central distribution roll has also been devised for the instant rotary printing press (see FIG. 6). The mechanism consists of an offset sun groove or ball race 39 similar to a barrel cam having a true pitch circle which contacts a single planetary ball 42 and which forms the pitch circle of the planetary hall, thus creating a ratio between pitch circles of the sun groove and planetary ball. The planetary ball 42 also makes contact with an outer annular groove or ball race 40 which also has a pitch diameter created by the angle of contact of the planetary ball. This angular contact may, as in the instant invention, create another pitch circle about the planetary ball. Thus, the planetary ball has one pitch circle relative to the sun groove 39 and a different pitch circle relative to the outer groove 40. The oscillation ratio of the sun groove is dependent upon a total of these ratios determining the planetary speed of the ball relative to the sun axle. It can be seen, therefore, that infinite oscillation ratios can be established by differentially rotating both the sun axle 38 and the outer annular race 40 or by compounding an offset outer race with the offset sun axle race. In the instant invention, one complete oscillation occurs upon one revolution of the planetary ball 42 around the sun axle 38, producing an oscillation rate of approximately two sun axle revolutions to one complete oscillation depending on the size of the sun groove 39 and the planetary ball 42.

The offset sun groove 39 is formed by a pair of side walls 41 converging inwardly for the two-point reception of the planetary ball member 42 mounted between a pair of ring members 43 within a mounting cap 44 and a sleeve member 45. The inner wall of each ring member is tapered as shown so as to present a pair of outwardly diverging walls within which the ball member 42 may be rotated while in contact with the side walls 41 of the groove 39. In this way, as the axle 38 is rotated, axial movement thereof will be effected between a leftward extent at the ball position seen in FIG. 6 and a rightward extent as when the axle is rotated through bringing the rearmost location of the groove 39 in contact with the ball 42. Any necessary adjustment of the bearing force of the ball against the side walls 41 can be accomplished by simply moving the ring members toward and away from each other thereby respectively increasing and decreasing the bearing force against side walls 41. Adjustment screws 46 (only one of which is shown) and shims 50 are provided for this purpose.

From the foregoing, it can be seen that an ink transfer system has been devised for improving the efficiency and transfer capabilities, for the various ink consistencies, of a transfer roll in use with rotary printing presses. The instant helical transfer roll, which can be easily installed and replaced in most printing press systems, assures a more perfect balance ofink film in the system as compared to other known devices. The unique design of the transfer roll surface allows an ink volume to be transferred consistent or equal to the usage requirements at any given point or area on the roll surface as determined by the printed image. The rate of transfer is varied by adjusting the speed of the fountain roll against the transfer roll running at less than press surface speed. Because both forward and reverse transfer is effected with this design, not only is complete reverse transfer possible as during a clean-up operation, but the system is capable of being run independently of the press thereby allowing the appropriate ink film to be established on all rolls without the actual running of the press. Contrary to some conventional continuous web presses, this would create a considerable waste product. However, without ink being consumed by the system, the ink transfer system, according to the present invention, will serve to merely recirculate the ink film between the fountain and distribution rolls during an ink film balance condition. Also, a simple but highly efficient manner of preventing leakage from the fountain has been devised simply through the use ofa fountain blade which is closely aligned with an end cap relief on the inner face of each cheek so that any leakage will result in beads of ink being directed onto the fountain roll and back into the fountain reservoir. Furthermore, a smooth oscillation of the rolls is effected by means of the instant oscillation technique in a manner which is simpler, more economical and requires less maintenance as compared to other known techniques because the instant device is an integral part of the oscillating axle and therefore exerts almost a totally direct axial force to effect oscillation.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. For example, the ink train of rollers may be slightly rearranged so that the transfer roll is in direct contact with the central distribution roll whereby an even more ink balanced system is effected because of the capability of the transfer roll to replenish ink in an almost direct ratio to ink removal. it is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

ll. In a rotary printing press, an ink transfer system comprising, in combination, an ink fountain reservoir, a fountain roll rotatably mounted in said fountain reservoir, a rotatable plate cylinder spaced from said fountain roll, a rotatable transfer roll adjacent said fountain roll and slightly spaced therefrom, and at least one rotatable distribution roll in an ink train of rollers between said plate cylinder and said transfer roll and in contact with the surface of said transfer roll, said transfer roll surface having a plurality of spaced grooves thereon, the side walls of adjacent grooves intersecting to form a sharp juncture and a trailing edge relative to the rotation of said transfer roll, one of the side walls of each groove being defined by a radial surface extending between the bottom of one groove to the sharp juncture of an adjacent groove, thereby defining a leading ramp in which its radius is substantially equal to the radial dimension of said transfer roll, whereby, during operation, said transfer roll is capable of simultaneously transferring an ink volume in a forward direction from said fountain roll by reason of said leading ramps and said trailing edges, respectively, thereby effecting a well balanced system as the ink volume is transferred consistent with the usage requirements at any given point on said transfer roll surface as determined by the printed image from the system.

2. The ink transfer system according to claim 1 wherein a plurality of rotatable ink distribution rolls is provided in the ink train of rollers, including a central distribution roll rotatable on an axle, said central roll axle being provided with means for producing a force directly along its axis for effecting oscillation ofsaid central roll during rotation thereof.

3. The ink transfer system according to claim 2 wherein said oscillation means comprises a ball member mounted within a longitudinally offset peripheral groove defining an inner race for said ball member on one end of said axle.

4. The ink transfer system according to claim 3 wherein a pair of ring members are provided as each having a sloping surface defining a groove therebetween defining an outer race for said ball member, said ring members being movable toward and away from each other for effecting, respectively, an increase and decrease in bearing force of said ball member within said inner race.

5. The ink transfer system according to claim l, wherein an adjustable fountain blade is provided in said ink fountain for controlling the ink film thickness on said fountain roll during rotation thereof.

6. The ink transfer system according to claim 5 wherein said fountain comprises a bottom support member and a pair of end members, each said end member having an aperture therein of a diameter substantially equal to the diameter of said fountain roll so as to snugly receive the ends of said fountain roll.

7. The ink transfer system according to claim 6 wherein means are provided on the inner faces of each said end member for directing beads of ink directly onto said fountain roll during leakage at said inner faces whereby said beads of ink may be directed back into said reservoir.

8. The ink transfer system according to claim 1 wherein means are provided for rotating said fountain roll, said fountain roll serving to regulate the rate of ink transfer in a forward and reverse direction upon rotation thereof at a speed between 0 and 6 /2 percent of press surface speed, the rate of reverse transfer increasing as the rotational speed of said fountain roll decreases, the rate of forward transfer increasing as the rotational speed of said fountain roll increases, and said transfer roll effecting a total reverse transfer as said fountain roll is rotated at a speed of or near 0 percent of press surface speed with no ink in said reservoir available for forward transfer. 

1. In a rotary printing press, an ink transfer system comprising, in combination, an ink fountain reservoir, a fountain roll rotatably mounted in said fountain reservoir, a rotatable plate cylinder spaced from said fountain roll, a rotatable transfer roll adjacent said fountain roll and slightly spaced therefrom, and at least one rotatable distribution roll in an ink train of rollers between said plate cylinder and said transfer roll and in contact with the surface of said transfer roll, said transfer roll surface having a plurality of spaced grooves thereon, the side walls of adjacent grooves intersecting to form a sharp juncture and a trailing edge relative to the rotation of said transfer roll, one of the side walls of each groove being defined by a radial surface extending between the bottom of one groove to the sharp juncture of an adjacent groove, thereby defining a leading ramp in which its radius is substantially equal to the radial dimension of said transfer roll, whereby, during operation, said transfer roll is capable of simultaneously transferring an ink volume in a forward direction from said fountain roll by reason of said leading ramps and said trailing edges, respectively, thereby effecting a well balanced system as the ink volume is transferred consistent with the usage requirements at any given point on said transfer roll surface as determined by the printed image from the system.
 2. The ink transfer system according to claim 1 wherein a plurality of rotatable ink distribution rolls is provided in the ink train of rollers, including a central distribution roll rotatable on an axle, said central roll axle being provided with means for producing a force directly along its axis for effecting oscillation of said central roll during rotation thereof.
 3. The ink transfer system according to claim 2 wherein said oscillation means comprises a ball member mounted within a longitudinally offset peripheral groove defining an inner race for said ball member on one end of said axle.
 4. The ink transfer system according to claim 3 wherein a pair of ring members are provided as each having a sloping surface defining a groove therebetween defining an outer race for said ball member, said ring members being movable toward and away from each other for effecting, respectively, an increase and decrease in bearing force of said ball member within said inner race.
 5. The ink transfer system according to claim 1, wherein an adjustable fountain blade is provided in said ink fountain for controlling the ink film thickness on said fountain roll during rotation thereof.
 6. The ink transfer system according to claim 5 wherein said fountain comprises a bottom support member and a pair of end membErs, each said end member having an aperture therein of a diameter substantially equal to the diameter of said fountain roll so as to snugly receive the ends of said fountain roll.
 7. The ink transfer system according to claim 6 wherein means are provided on the inner faces of each said end member for directing beads of ink directly onto said fountain roll during leakage at said inner faces whereby said beads of ink may be directed back into said reservoir.
 8. The ink transfer system according to claim 1 wherein means are provided for rotating said fountain roll, said fountain roll serving to regulate the rate of ink transfer in a forward and reverse direction upon rotation thereof at a speed between 0 and 6 1/2 percent of press surface speed, the rate of reverse transfer increasing as the rotational speed of said fountain roll decreases, the rate of forward transfer increasing as the rotational speed of said fountain roll increases, and said transfer roll effecting a total reverse transfer as said fountain roll is rotated at a speed of or near 0 percent of press surface speed with no ink in said reservoir available for forward transfer. 